Lancing devices are utilized for penetrating the skin of a human or animal subject at a lancing site to obtain a sample of blood or other body fluid for medical testing, as in blood-typing or blood-glucose testing. Known lancing devices commonly include a housing containing a drive mechanism, a charging mechanism for energizing the spring or other drive means of the drive mechanism, and a release mechanism for releasing the drive mechanism upon actuation. A lancet is typically propelled by the drive mechanism from a retracted position within the housing to an extended position wherein a sharp tip portion of the lancet projects from the housing to prick the subject's skin at a desired lancing site. A depth-control mechanism can optionally be provided for adjusting the penetration depth of the lancet.
Many known lancing devices use drive mechanisms that rely on a balance between two linear (compression) springs for driving and retracting the lancet, resulting in the possibility of the lancet needle piercing the subject multiple times. Additionally, many known lancing devices use depth-control mechanisms for controlling the depth of puncture of the lancet needle by stopping the forward motion of the lancet, resulting in an impact that can be undesirably felt and/or perceived by the subject. Some known lancing devices may allow oscillation of the lancet in response to the balance of forces imparted by the drive and return springs, creating a potential for pricking the skin of the subject multiple times, which can unnecessarily result in pain to the subject. Additionally, some known lancing devices have depth-control mechanisms for stopping the forward motion of the lancet carrier by contact with a stop surface, which can result in impact, vibration or sound perceived by the user, and potentially increasing the perception of pain from lancing.
There is an ongoing need for improvements to lancing devices and drive mechanisms for lancing devices to increase convenience and compliance with a prescribed testing regimen, and to reduce the perception of pain by testing subjects. It is to the provision of improved lancing devices and drive mechanisms for lancing devices meeting these and other needs that the present invention is primarily directed.